Mechanical pencil



March 15, 1932. J. w. WELSH 1,849,210

MECHANI CAL PENCIL Filed March 21, 1929 2 Sheets-Sheet 1 was; 2 i: A :15: 20 "F n 7/ I i 8 z 3% 55 WI A/ 2 g d 4 .A ii: 24 I E1? 3 H 7/3 5/ 551 58 24 \.i j 43 March 15, 1932. J, w. WELSH MECHANICAL PENCIL FiledMarch 21, 1929 2 Sheets-Sheet 2 [mm 2101" Jaw/rues W Wetsh Patented Mar.15, 1932 UNITED STATES PATENT OFFICE JAMES WILSON WELSH, OF PROVIDENCE,RHODE ISLAND, ASSIGNOB TO THE WELSH MANUFACTURING GOMPANY, OFPROVIDENCE, RHODE ISLAND, A CORPORATION OF RHODE ISLAND MECHANICALPENCIL Application filed March 21, 1929.. serial No. 348,839,

The present invention relates to marking devices, and more particularlyto mechanlcal pencils.

An object of the invention is to improve.

upon devices of the above-described character, to the end that theirefliciency may be 1ncreased, their construction simplified and theircost of manufacture reduced. Other and further objects will be explainedhereinafter and will be particularly pointed out in the appended claims.I

In the accompanying drawings, illustrating a preferred embodiment of thepresent invention, Fig. l is an elevation; Flg. 2 1s a centrallongitudinal section taken through the casing and the cap, substantiallyupon the line 22 of Fig. 1, looking in the direction of the arrows; Fig.3 .is a section, upon a larger scale, taken upon the line 33 of 93 Fig.2, looking in the direction of the arrows; Fig. 4 is a fragmentary,enlarged view of the body of the pencil, with the casing removed, theparts being shown in positions similar to those of Fig. 2; Figs. 5 and 6are,

* sections taken substantially upon the lines 5-5 and 66 of Fig. 4,looking in the directions of the arrows; Figs. 7 and 8 are views, upondifierent scales, of details; Fig. 9 is a View of a further detail; andFig. 10 is a 39 view of a modification.

The pencil-carrying body is housed in a casing 2 (Figs. 1, 2 and 3). Thepencil may be retained in the owners pocket by a clip 6 having aterminal prong 8 and an intermediately disposed prong 9 (Figs. 2 and 9)extending through openings 10 and bent over against the inner wall 12 ofthe casing. The clip 6 is shown in Fig. 9 before assembly with thecasing2. In such condition, the prongs are shown extending medially ofthe sides 11 and 13 of the cli 6 at right angles to the body of theclip, t e prong 9 being cut out of the body of the clip. Where metalcasings 2 are used, the o ening's 10 are previously formed in thecasing, but when celluloid or other suitable non-metallic casings 2 areemployed, the prongs may drive their own openings into the casing.

The lead or other marker 14 projects from the forward, conical end ofthe casing and is gradually fed forward, as it is used up, by rotaryfeed mechanism hereinafter to be described. An eraser 16 at the other orrear end of the pencil is ordinarily protected against dirt and thelikeby a'cap 18, but may be put intoservice when the cap is removed.

The lead 14 is frictionally clutched or held by a plunger tube 20through one end 22 of which it projects, as will be understood moreparticularly from Figs. 2, 3 and 4. The tube 20 is slidably mounted in aslotted tube 24. The lower end 26 of the slotted tube 24 may rest in aguide groove 28 at the lower end of the casing, as will be understoodfrom Fig. 2. The guide groove 28 may, however, be formed in a separatemetal piece 29 that is screwed into the lower end of the casing 2 at 31,particularly ifthe casing 2 is of celluloid or other non-metallicmaterial. The lower end 22 of the marker-holding tube 20 is normallywithin *the slotted tube 24, as shown in Figs. 2 and 3, but may beprojected through the lower end 26 of the slotted tube 24, as shown inFig. 4, towards the end of its feed movement through the slotted tube24, as hereinafter described. This happens, of course, when th lead 14has become nearly completely used up, and the-small, still-remaining,portion of the lead is then forced out of the end 22 of the clutch tube20 by a marker plunger or push rod 32 that is slidably mounted in theclutch tube 20. Normally, as will be described hereinafter, themarker-holding or clutch tube 20 and the plunger push rod 32movelongitudinally through the slotted tube 24 as a unit, but at theirlower limit of movement, the clutch tube 20 is held stationary and thepush rod 32 is advanced therethrough, into the position illustrated inFig. 4, to expel the lead. Upon a reverse movement of the parts, on theother hand, the push rod 32 first withdraws into the clutch tube 20, topermit the insertion of a new lead into. the same, and then the clutchtube 20, the lead held thereby and the plunger push rod 32 may bewithdrawn into the slotted tube 24 in readiness for a new advance of thelead '14. It is thus possible to have as much lead projecting from thecasing as desired, and if the lead should, by

any chance, be advanced too far out of the I casing, all that isnecessar is to retract the push rod 32 and the hol 'ng tube as a.

unit, carrying the lead with it,'until just so much lead only projectsfrom the casing as is desired. The lead may similarly be withdrawn intothe casing to protect it against breakage when the pencil is not in use.The plunger push rod 32 may be advanced throughthe end 22 of the holdingtube 20 up to the very end 22 of the tube, so that practically the verylast tip of the lead 14 may be used up, for the tube 20 will continue toclutch the lead 14 even though only a ver small portion of it is left.

The tube 20 is intermediately provided, near its u per end, with aprojection 33., A portion 0 tion 33 is slotted longitudinally at for aconsiderable distance to permit free sliding movement between the wallsof the slot of a projection 34 that is provided upon the push rod 32.The purpose of the slot 42 in the slotted tube 24is to receive theprojections 33 and 34 and keep them alined in the slot 42, therebypermitting free slidable movement through the sloted tube 24 of theplunger tube 20 and the plunger push rod 32.. A preferred method ofmanufacturing the tube 20 is to die a suitably shaped blank out of sheetsteel, and then to fold it, as shown. The upper end 54 of the tube 20 isclosed to fprevent the projection 34 from riding out o the slot 40. A

The preferred mechanism for advancing and retracting the plunger-holdingtube 20 and the plunger push rod 32 will now be\described. Theprojections 33 and 34 of the tube 20 and the push rod 32,- respectively,are adapted to be engaged b a'helical or spiral thread 36 upon a rotatale sleeve 38 that is mounted to enclose the slotted tube 24. As

will be explained hereinafter, the spirallythreaded sleeve 38, thoughrotatable relative to the slotted tube 24, is held against longitudinalmovementrelative to the slotted tube 24. The sleeve 38 may be made inany desired manner, as by spirally coiling a stamped-out, flat,sheet-metal blank. As i1- lustrated in Figs. 2 and 3, the projections 33and-34 normally engage spaced portions of the spiralthread 36., so thattheprojections 33 and 34 will normally remain separated from each otherby a constant distance, As the sleeve 38 is rotated about the slottedtube 24, therefore, the holding tube 20' and the push rod 32 will beadvanced or retracted through the slotted tube 24 as 'a unit, accordingto the direction of rotation of the sleeve 38. The

projections 33 and 34' will slide freely through the slot 42 during suchrotationof the spirally threaded sleeve 38. To advance or retractthelead 14, therefore, all that is necessary is to rotate the spiralsleeve 38, holding the slotted tube 24 stationary.

the tube 20 just above the projec- 2 guano According to the preferredconstruction the spiral sleeve 38 is ada ted to be rotated by securingit to a manua y rotatable tube 46 that projects through the casing atthe rear or eraser end of the encil. This may be effected in any desiredway, preferably by inserting the upper end 44 of the tube 38 in thelower end 45 of the tube 46, and soldering or swedging thepartstogether. To bring this about, of course, the diameters of theparts 44 and 45 should preferably be such that the former will just fitinto the latter. As the cap 18 is fitted frictionally on the upperenlarged or expanded end 47 of the tube 46, the lead 14 may be advancedor retracted at will by rotating the cap 18 in one direction or theother, while holding the slotted tube 24 against rotation. The purposeof enlargin the tube 46 at 47 is two fold: first, the tu e 46 is enabledto fit better in the casing 2, asshown in Fig. 2; and secondly, itprovides a seat for the eraser 16. Or, the tube 46 may be of enlargeddiameter to start with, and the end 45 of the tube may, in that event,be reduced in diameter. The enlarged portion 47 of the tube 46 isslotted at 49, to provide a resilient 'holding action upon the eraser16.

It is now necessary to describe how the slotted tube 24 is held againstrotation during the rotatable movement of the sleeve 38. After the partsthus far described, with the exception of the cap 18 and the casing 2,are assembled together, they are inserted as a unit in a barrel 51. Thebarrel 51 is substantially of the same length as the sleeve 58 and pro-59, permitting the lower end of the spirally threaded sleeve 38 toengage against the end plate 57. The opening 59 is provided with a keylock or other projection 68 to engage against the slot 42 of the slottedtube 24 to prevent the tube 24 from rotating relative to the end plate57 A collar 61 1S slipped over the lower end 26 of the slotted tube 24untiPit contacts with the end plate 57, and is secured in place in anydesired manner. A very effective securing means consists in merelystriking out, or expanding outward, at 63, a 'portion of the wall of thetube 24 just below the collar 61. j I

The parts thus far described, except for the casing 2 and the cap 18,will be held together as a'unit, if the slotted tube 24 is caused to beheld in aplace. The upper end of the slotted tube 24 is thereforeprovided with a The shank 65 is secured in the slotted tube 24 in anydesired manner, as by soldering. The head 67 is of greater diameter thanthe diameter of the slotted tube 24, and is disposed outside of theslotted tube in order that it may engage against the upper end 44 of thesleeve 38. The slotted tube 24 is thus prevented from slippinglongitudinally out through the opening 59 and the parts are heldtogether as a unit.

The rivet serves a further purpose in that it acts as a bottom for thetube 46. The tube 46 may then serve as a chamber for extra leads 14. Toremove an extra lead 14, all that is necessary is to unseat the eraser16, thereby affording access to the lead chamber,

To permit inserting this unit into the easing 2, the slot 53 of thebarrel 51 1s made wide enough so that the prongs 8 and 9 may readily bepassed therethrough. 'Thepurpose of the other slot 55 is to strengthenthe spring action of the spring walls 69 and 71 that are formed on bothsides of the slots 53 and 55, without causing these spring walls toproduce a bulge in the casing 2. It is, therefore, made narrower thanthe slot 53. The walls 69 and 71 are bent outward to engage frictionallyagainst the inner walls of the casing 2. As the walls 69 and 71 aresubstantially as long as the sleeve 38, they bind against the innercylindrical walls of the easing 2 throughout a substantial area abovethe conical end of the casing. Sufficient spring tension is thusprovided 'to hold the unit frictionally in position in the casing durlngthe rotation of the sleeve'38, but the unit may readily be withdrawnfrom the casing, in opposition to the sprin tension of the spring walls69 and 71, by pul ing outward upon the portion 47 of the tube 46.

In operation, the turning movement of the cap 18 will be communicated tothe spirally threaded sleeve 38. The projections 33 and 34 will thus beadvanced and retracted according to the direction of rotation. of thecap 18, carrying the lead 14 with them as a unit. At the forward limitof slidable movement of the holding tube 20, the projection 33, beingnearer to the end plate than the projection 34, will ride off the openend 58 of the thread 36, and become seatedin a depressed stop 73 that isprovided in the end plate 57. As the holding tube '20 can not advancebeyond that point, further rotative movement of the sleeve 38 will causethe projection 34 to advance toward, and into engagement with, the stop33, as shown in Fig. 4, with the result that, as the push rod 32advances through the holding tube 20, it will expel the lead. A reverserotatable movement of the sleeve 38 will cause, first, the projection34,'and then, the projection 33, to engage with the thread 36, afterwhich a new lead may be inserted in the end 22 of the holding-tube 20. i

As an alternative construction, the wall at the lower end of the sleeve38 may be cut away at a point external to the thread to provideprojection, a longitudinally slotted tube within which the plunger isslidably mounted, the longitudinal slot of the tube permitting free'sliding movement of the projection between the walls of the slot, a plughavin ted tube and a head of greater diameter than the diameter of theslotted tube disposed outside of the slotted tube, the head beingcontinuous so as to close the slot of the tube, whereby the head mayserve as the closed bottom of a receptacle, a sleeve enclosingtheslotted tube with the head of the plug engaging an end of the sleeve,the sleeve being rotatable relative to the, slotted tube, meanscooperating with the head of the plug to hold the sleeve and the slottedtube against relative longitudinal movement, the sleeve having a spiralthread adapted to engage the a shank secured in one end of theslotprojection to advance and retract the plunger according to thedirection of relative rotation of the sleeve and the slotted tube, acas-v ing, and means for holding the slotted tube against rotativemovement in the casing, whereby rotative movement of the sleeve in thecasing will effect longitudinal movementof the. plunger in the slottedtube.

2. A device of the class describd having, in

combination, a marker plunger having a projection, a longitudinallyslotted tube within which the plunger is. slidably mounted, thelongitudinal slot of the tube permitting free sliding movement of theprojection between the walls of the slot, a plug having a shank securedin one end of the slotted tube and a head of greater diameter than thediameter of the slotted tube disposed outside of the slotted tube, asleeve enclosing the slottedtube with the head of the plug engaging anend of the sleeve, the sleeve being rotatable relative to the slottedtube, means cooperating with the head of the plug to hold the sleeve andthe slotted tube against relative longitudinal movement, the sleevehaving a spiral thread adapted to engage the projection to advance andretract the plunger according to the direction of relative rotation ofthe sleeve and the slotted tube, a chamber tube, the end of the sleevenear the plug being secured in an end of the chamber tube, whereby thehead of the plug forms a closed bottom for the chamber tube, and acasing in which the slotted tube is held againstrotative movement, withthe other end of the chamber tube projecting through an end of thecasing, whereby roplunger in the slotted tube.

3. In a device of the class described having a marker plunger, a casing,a clip, and means extending through the inner walls of the casing forholding the ch on the cas1ng, means for advancing an retracting theplunger in the casing including a barrel having two longitudinal slots,whereby spring walls are formed between the slots, one of the slotsbeing wide enough'to permit the extending means to be passedtheret-hrough when the barrel is slid into the casing, and the otherslot being narrower than the said one slot, whereby the spring walls aremade relatively wide so that they are adapted to engage frictionallyagainst the inner walls of the casing with suflicient spring tension tohold the plunger frictionally in pesition 1n the casing, but withoutspring tension great enough to produce a bulge in the casing.

4. As an article of manufacture, a barrel having two longitudinalslots,wherebyspr1ng walls are formed between the slots, one of the slotsbeing wide enough to permit an article of substantial width to be passedtherethrough, the other slot being narrower than the said one slot,whereby the spring walls,

, whereby spring walls are formed'between are made relatively wide, thebarrel having an end late bent over at an angle to the axis of thearrel, and the end plate be ng provided with an opening.

5. As an article of manufacture, a sheet metal barrel having twolongitudinal slots,

the slots, the barrel having an end plate bent over at an angle to theaxis of the barrel, and

the end plate being provided with an opening, a slottedmarker-plunger-holding tube extending through the opening and anelevated sto the late having means for preventing rotiition 0 1 theslotted marker-plunger-holding tube. I

6. A device of the class described havlng, in combination, a markerplunger having a projection, a longitudinally slotted tube within whichthe plunger is slidably mounted, the longitudinal slot of the tubepermitting tree sliding movement of the projection between the walls ofthe slot, a plug having a shank secured in one end of the slotted tubeand a head of greater diameter than the diameter of the slotted tubedisposed outside ,of the slotted tube, a sleeve enclosing the slottedtube with the head of the plug engaging an end of the sleeve, the sleevebeing rotatable relative to the slotted tube and having a spiral threadadapted to engage the projection to advance andretract the plungeraccording to the direction of relative rotation of the sleeve and theslotted tube, a barrel in WhlCh theslotted tube in engagement with theend plate,

sleeve is rotatably disposed, the barrel having an end plate providedwith an opening through which the slotted tube extends, means engagingthe end plate and cooperating with the head of the rivet to hold thesleeve and the slotted tube against relative longitudinal movement,whereby rotative movement of the sleeve relatively to'the barrel willeffect longitudinal movement of the plunger in the slotted tube, andmeans for slot-ted tube anda head of greater diameter than the diameterof the slotted tube disposed outside of the slotted tube, a sleeveenclosing the slotted tube with the head of the plug engaging an end ofthe sleeve, the sleeve being rotatable relative to the slotted tube andhaving a spiral thread spaced portions of'which are adapted to engagethe alined projections to advance and retract the holding tube and theplunger therein according to the direction of relative rotation of thesleeve and the slotted tube, a barrel in which the sleeve is rotatablydisposed, the barrel having an end plate engaging the other'end of thesleeve and provided with an opening through which the slotted tubeextends, a collar upon the means upon the slotted tube engaging thecollar and cooperating with the head of the rivet to hold the sleeve andthe slot-ted tube against relative longitudinal movement, wherebyrotative movement of the sleeve relatively to the barrel will efiectlongitudinal movement of the plunger and the holding tube in the slottedtube, and means for holding the slotted tube from rotation with respectto the barrel.

8. A devlce. of the class described having, in combination, a markerplunger having a projection, alongitudinally slotted tube within whichthe plunger is slidably mounted and having a projection near one end,the longi tudinal 'slot of the slotted tube permitting free slidingmovement of the marker-plunger through adapted to engage themarker-plunger projection to advance and retract the plunger accordingto the direction of relative rotation of the sleeve and the slottedtube, a barrel which the sleeve is rotatably disposed, a'casing, meansdisposed near the other end of the slotted tube and cooperating with theslotted-tube projection to hold the plunger, the slotted tube, thesleeve and the arrel together as a unit against relative longitudinalmovement but permitting relative rotative movement between the sleeveand the slotted tube, and means for effecting rotative movement of thesleeve relative to the slotted tube in the casing to producelongitudinal movement of the plunger in the slotted tube. 9. A device ofthe class described having, in combination, a marker plunger having aprojection, a longitudinally slotted tube within which the plunger isslidably mounted and havinga projection near one end, the longitudinalslotof the slotted tube permitting free sliding movement of the markerplunger projection between the walls of the slot, a sleeve enclosing theslotted tube, the sleeve being rotatable relative to the slotted tubebut being held against longitudinal movement relative to the slottedtube, the

.sleeve having a spiral thread extending therethrough adapted to engagethe projection to advance and retract the plunger according to thedirection of relative rotation of the sleeve and the slotted tube, achamber tube. one end of the sleeve being secured in an end of thechamber tube. a barrel in which the sleeve is rotatably disposed, acasing, and means disposed near the other end of the slotted tube andcooperating with the slottedtube projection to hold the plunger, thetubes, the sleeve and the barrel together as a unit against relativelongitudinal movement but permitting relative rotative movement betweenthe sleeve and the slotted tube, and the other end of the chamber tubeprojecting through one end of the casing, whereby rotative movement ofthe chamber tube in the casing will effect a rotative movement of thesleeve relatively to the slotted tube and thereby efiect longitudinalmovement of the plunger in the slotted tube.

10. A device of the class described having,

' in combination. a marker plunger havin a projection. a longitudinallyslotted tube within which the plunger is slidably mounted. thelongitudinal slot of the slotted tube permitting free sliding movementof the projection between the walls of the slot, a sleeve enclosing the.slotted tube, the sleeve having a spiral thread adapted to engage theprojection to advance and retract the plunger according to the directionof relative rotation of the sleeve and the slotted tube. a barrel inwhich the sleeve is rotatably disposed. the barrel having an end plateprovided with an opening through which the slotted tube extends, m'eansfor efiecting rotative movement of the sleeve relatively to the barrelto effect longitudinal movement of the pioneer in the slotted tube, twomeans respectively provided near opposite ends of the slotted tube andrespectively on aging the end late and the opposite end of the sleevefor hol ding the parts. together as a unit against relative longitudinalmovement but permitting relative rotative'movement between the sleeveand the slotted tube, and a casing, the unit being adapted to beinserted in the casing.

In testimony whereof, I have hereunto subscribed my name.

JAMES WILSON WELSH!

